1. Field
The present invention relates to transmission technology, and particularly to information analysis systems for transmitting information that requires timing synchronization.
2. Description of the Related Art
At scenes of disaster, various types of measuring instruments for measuring biological information are used. Biological information that has been measured is transmitted to biological information monitoring devices via a communication network. Operation of the biological information monitoring devices performed by observers facilitates relief activities (for example, Patent Document 1).
Patent Document 1: Japanese Patent Application Publication No. 2011-212167
Firefighters, etc., who are engaged in relief activities at scenes of disaster are at risk of losing their lives in the line of duty. Particularly in the United States, the main cause for a loss of life in the line of duty is a heart attack at scenes of disaster, followed by suffocation due to smoke or toxic gas, or external injuries caused by dangerous operations associated with rescue or firefighting. In order to prevent this, detection of biological information and circumstances of the firefighters is desired. For example, if abnormality is detected when the firefighters' cardioelectricity, heart rate, etc., are monitored as biological information, some kind of treatment should be provided accurately and promptly. In order to find abnormality through the detection of biological information, multiple electrocardiographic monitors are worn at multiple sites of the body in the case of an electrocardiogram, and a diagnosis is made based on changes in respective waveforms in the same time period. Abnormality is also detected based on multiple different pieces of biological information such as an electrocardiogram, a pulse wave, etc., in the same time period.
By putting sensors for detecting biological information on firefighters and using wireless technology and Internet technology, a diagnosis can be made at remote locations. If multiple sensors are used to increase the accuracy of abnormality detection, timing synchronization between signals of the sensors is necessary in that case. In the case of transmitting the signals of the sensors with use of the wireless technology and the Internet technology, a time difference is generated between the signals depending on a traffic condition even when the signals are transmitted at the same time. As a result, even pieces of biological information that are received at the same time by the receiver, the pieces of biological information are not always those acquired at the same timing. Therefore, it is difficult to make a diagnosis using multiple different pieces of biological information such as an electrocardiogram, a pulse wave, etc., in the same time frame.